Safety belts are designed to protect the occupants of a vehicle during events such as automobile collisions. In low-speed collisions, the occupants are generally protected from impact with objects located inside the vehicle such as the windshield, the instrument panel, a door, the side windows, or the steering wheel by the action of the safety belt. In more severe collisions, however, even belted occupants may experience an impact with the car's interior. Airbag systems were developed to supplement conventional safety belts by deploying into the space between an occupant and an interior object or surface in the vehicle during a collision event. The airbag acts to decelerate the occupant, thus reducing the chances of injury to the occupant caused by contact with the vehicle's interior.
Many typical airbag systems consist of several individual components joined to form an operational airbag module. Such components generally include an airbag cushion, an airbag inflator, a sensor, and an electronic control unit. Airbag cushions are typically made of a thin, durable fabric that is folded to fit into a compartment of a steering wheel, dashboard, interior compartment, roof, roof rail, roof compartment, or other space in a vehicle. The airbag inflator is in fluid communication with the airbag cushion, and is configured to produce a gas to inflate the cushion when it is needed. The sensors detect sudden decelerations of the vehicle that are characteristic of an impact or angular accelerations that are characteristic of a rollover event. The readings taken by the sensors are processed in the electronic control unit using an algorithm to determine whether a collision or rollover has occurred.
Upon detection of an impact of sufficient severity, the control unit sends an electrical signal to the inflator. The inflator uses one of many technologies currently known in the art to produce a volume of an inflation gas. The inflation gas is channeled into the airbag, inflating it. Inflation of the airbag causes it to deploy from its stored location, placing it in a position to receive the impact of a vehicle occupant. In primary impact airbag cushions, after contact of the occupant with the airbag and the corresponding deceleration of the occupant, the airbag rapidly deflates. To accomplish this, the inflation gas is vented from openings in the airbag, deflating it and freeing the occupant to exit the vehicle. In airbag cushions such as rollover curtains intended to protect a vehicle occupant during a rollover event, the airbag is not immediately vented. Instead, the airbag is maintained in a sealed condition for a period of time to maintain inflation and cushioning capacity. This period of time may, in some instances be at least six seconds in length.
As experience in the manufacture and use of airbags has increased, the engineering challenges involved in their design, construction, and use have become better understood. Most airbag systems are designed to rapidly inflate and provide a cushion in proximity to a vehicle occupant. Inflatable curtain airbag cushions are configured to be rapidly placed alongside a vehicle occupant between the occupant and the side doors, windows, and pillar structures of the vehicle.
The placement of inflatable curtain airbag cushions is determined based on carefully-researched and tested presumptions made of the position occupied by a vehicle occupant in a vehicle during normal operation of the vehicle. Curtains are configured to deploy into a space not predicted to be occupied and to fill much of that space, preventing interaction of the occupant and the side of the vehicle. As a result, a vehicle occupant generally enjoys optimal protection from a specific airbag when the occupant is in the presumed range of positions when the airbag deploys.
In some situations, injuries have been noted to occur when a vehicle occupant is “out-of-position” with regard to the presumed position discussed above. Some such injuries have been attributed to incidents in which vehicle occupants located out-of-position during the deployment of an airbag cushion are located in the path of the inflating cushion. Currently available airbag systems have little ability to regulate the trajectory of an inflatable curtain airbag cushion during deployment. As a result, injuries may occur along the inflation path of the inflatable curtain before it has reached its final position and full inflation.
Another issue presented by many specific airbag applications is the need to assure consistent placement of the airbag cushion after deployment. Inflatable curtain airbag cushions face some deployment difficulties as a result of their location in the roof. Improper or incomplete deployment may be caused by curtain becoming tangled in the roof trim or other interior features of the vehicle. Deployment problems may cause poor placement of the inflated curtain, providing less-than-optimal protection to the vehicle occupant. Attempts have been made in currently-used inflatable curtain airbag systems to minimize such problems, but they persist. As a result, it would be beneficial to provide an inflatable curtain airbag system in which the trajectory of the deploying airbag curtain may be modified along its length to enhance the ability of the curtain to predictably exit roof trim, avoid obstacles in potential deployment paths of the curtain, and to deploy away from the predicted position of a vehicle occupant.
Accordingly, a need exists for systems for use with inflatable curtain airbag cushions that provide deployment trajectory control for at least a localized portion of the airbag cushion. It would be specifically beneficial to provide an inflatable curtain trajectory bracket capable of providing predictable deployment of an inflatable curtain locally inboard to properly exit roof trim and locally outboard in regions near a vehicle occupant's predicted position. Such inflatable curtain airbag cushion trajectory regulation devices and methods for their use are provided herein.